List assignment

Question

I have lists like this,

a=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
b=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
c=['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

Here I am trying to replace each element of list 'a' one by one with the element of list 'c'. I tried this code:

for i in range(len(a)):
    a[i]=c[i]
    print a
    a=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']

With this code I am getting correct output which is:

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 1']

But when I replaced the last statement(assigning) as

for i in range(len(a)):
    a[i]=c[i]
    print a
    a=b

list 'b' also updating. How can i achieve this with out assigning the entire list directly.

You keep putting back the old value of `a` with `a=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']` — Barmar, Mar 29 '17 at 07:45

ma3oun · Accepted Answer · 2017-03-29T08:48:52.463

1

Just replace the last line with:

a=b[:]

edited Mar 29 '17 at 08:48

answered Mar 29 '17 at 07:55

ma3oun

3,681
1
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33

i am getting error as ,TypeError: 'module' object is not callable – sowji Mar 29 '17 at 08:33
its working for me, thank you. – sowji Mar 29 '17 at 09:04

score 1 · Answer 2 · answered Mar 29 '17 at 08:08

1

You can try copy moduel in python

from copy import deepcopy
a = deepcopy(b)

answered Mar 29 '17 at 08:08

Prashant Puri

2,324
1
15
21

Thank you, its worked for me. – sowji Mar 29 '17 at 08:33
@sowji : Most Welcome..If its help you, then appreciate answer by upvoting it. – Prashant Puri Mar 29 '17 at 08:57

Montmons · Answer 3 · 2017-03-29T08:15:44.273

Really unsure of what it is you are asking but seems to me you are trying to achieve something like:

for i in range(len(a)):
    a[i]=c[i] # change only the specified itemnr of list a with the same itemnr of list c.  
    print a # prints (as you've seen and mentioned to be correct: list a with one of its items replaced by an item of list c)
    a[i]=b[i] # Since list a[i] has been set to c[i] earlier in the loop doesn't mean it can't be changed again in the same loop.
    print a

Output:

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']

Or, if you want to process list b similar to a you could also simply do (since list b has the exact same length as a):

for i in range(len(a)):
        a[i]=c[i] 
        print a 
        b[i]=c[i]
        print b

Output:

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

Or you could do:

for x in [a,b]:
    for i in range(len(x)):
        x[i]=c[i]
        print(x)

Output:

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

List assignment

3 Answers3